L & S C30Y Lecture Notes - Lecture 5: Retrovirus, Drug Resistance, Xx Male Syndrome
1 Feb 2017
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Document Summary
Bacteria and their viruses do it horizontal gene transfer. Xq28 the story of the gene for homosexuality. To a biologist it"s all about the successful exchange of genes. Bacteria have sex through horizontal dna transfer: move gametes from one to another. One bacterium contains a plasmid to be transferred: f=fertility plasmid, one f+ and one f- A connection forms and the plasmid is copied. Both bacteria now contain the plasmid: two f+ plasmids. The recipient may even integrate the plasmid into its chromosome. The bacteria need opines, and give the plant the genes that the plant needs to make opines for the bacteria. Crown gall bacterially transmitted tumor forming genes: bacteria need unusual amino acids, insert genes into the plant to make these amino acids. Double-stranded dna binds to the plasma membrane. Other enzymes break down one dna strand. Dna replaces a portion of the bacterium"s dna. Cell synthesizes new phages that incorporate phage dna and, mistakenly, some host dna.
